Recently, with the explosive prevalence of the Internet, a LAN (Local Area Network) is frequently constructed in offices, houses and the like. Further, because cable wiring is troublesome, there is an increasing need for so called wireless LANs which construct a LAN wirelessly, which is aided by progress in digital wireless communication technologies. Wireless LANs are expected to be used in large numbers, because the devices can be used in mobile terminals such as notebook computers in mobile environments.
As a representative technology of the wireless LAN, there is IEEE 802.11 which has already been standardized in IEEE (Institute of Electrical and Electronics Engineers). This standardized technology defines from a physical layer to a MAC (Media Access Control) layer, being a lower layer of a data link in an OSI model, and can be replaced with Ethernet™ which is a wired LAN transmission channel. Further, IEEE 802.11 can provide a roaming function as an additional function due to being wireless.
There is an AV control system, using a GUI (Graphical User Interface), in which a plurality of AV (Audio Visual) devices are radially connected with a television (referred to as “TV” hereinafter) receiver capable of graphic display, information regarding each AV device is displayed on a display screen of the TV receiver using icons or the like and by operation of a remote controller; selection and operation of the icons or the like allows dedicated operation of each AV device. The AV device is explained below using a video tape recorder (referred to as a VTR hereinafter) as an example.
In such an AV control system, when a VTR is operated, two selection operations are necessary: one is an operation for selecting the VTR to be operated from a plurality of VTRs; and the other is an operation performed on the selected VTR, for selecting a desired execution function from a plurality of execution functions such as recording, reproducing, stopping, and rewinding.
The TV receiver stores graphic display data regarding each VTR in a table form. In response to an operation request to a desired VTR from a remote controller operated by a user, the TV receiver displays on a display screen an operation window corresponding to the VCR in a position having a one-to-one relation with the VTRs, and displays a plurality of function buttons in the operation window which indicate a variety of functions. When the user selects with a cursor one of the displayed function buttons, the TV receiver instructs the VTR to carry out the selected function.
The operation window is superposed on a usual screen image. When a plurality of operation windows are to be displayed, the process is repeatedly carried out a number of times corresponding to the number of the operation windows.
FIG. 10 is a block diagram illustrating one example of the AV control system. As illustrated in FIG. 10, an AV control system 200 has a structure in which four VTRs 202 through 205 are radially connected with a TV receiver 201. In the AV control system 200, for example, when the user causes a VTR (A) 202 to perform a reproducing operation, the following operation is performed using the GUI.
(1) First, the control section of the TV receiver 201 checks whether a plurality of control cables 206 through 209, connected to the TV receiver 201, are connected to VTRs 202 through 205 respectively, finds out the machine-types of the connected VTRs 202 through 205, and registers the machine-types in a machine-type table.(2) Next, when the user uses a remote controller 210 and specifies a menu display on the TV receiver 201, four icons corresponding to VTR (A) 202 through VTR (D) 205 are displayed on four points of a display screen such as a CRT, and a cursor is also displayed.(3) Next, when the user uses the remote controller 210 and specifies with the cursor an icon corresponding to the VTR (A) 202, an operation window corresponding to the VTR (A) 202 is displayed on the position of the icon. In the operation window, a recording button, a reproducing button, a stopping button, a rewinding button and the like are displayed.(4) At that time, for example, when the reproducing button in the operation window of the VTR (A) is depressed, a command for beginning a reproducing operation is transmitted to the VTR (A) 202 from the TV receiver, and at the same time a command for instructing the TV receiver to switch to a video input from the VTR (A) 202 is sent. As a result, the reproducing operation of the VTR (A) 202 is started, and at the same time an output of the VTR (A) 202 is inputted to the TV receiver, and accordingly an image reproduced by the VTR (A) 202 is displayed on the display screen.
In the above conventional example, graphic display data is included in the TV receiver. On the other hand, as disclosed in Patent Document 1, there is a system in which graphic display data is dispersedly stored by each of a plurality of AV devices, and thereby the TV receiver performs graphic display of only a response to a request, which allows display of a new AV device. Further, as disclosed in Patent Document 2, there is a system which allows display of error data from the AV device side, when a failure occurs in the AV device. Further, Patent Document 3 discloses an apparatus which causes a structure display of a network system to include display of functions of individual devices, so as to simplify operations of the devices.
Here, Patent Document 1 is Japanese Laid-Open Patent Publication 149325/1997 (Tokukaihei 9-149325) (published on Jun. 6, 1997), and particularly FIG. 1 of the publication.
Further, Patent Document 2 is Japanese Laid-Open Patent Publication 336778/1995 (Tokukaihei 7-336778) (published on Dec. 22, 1995), and particularly FIG. 1 of the publication.
Further, Patent Document 3 is Japanese Laid-Open Patent Publication 337763/2001 (Tokukai 2001-337763) (published on Dec. 7, 2001), and particularly FIG. 1 of the publication.
However, the conventional AV control systems as described above have a problem that it is difficult to know whether a nearby AV device is operated, or a distant AV device connected to a network is operated. Particularly, when an AV device exists in a distant room or when a lot of AV devices exist, it is difficult to find out a desired device on a display on a console.
The present invention is made in view of the foregoing problems, and its object is to provide a display device, a wireless communication system and the like which make it easy to know an estimated positional relationship among AV devices and the like, connected so as to perform wireless communication.